Tie a car salesman’s bonus to sheer volume and he will slash prices until the dealership goes bankrupt while still collecting his bonus. That is Goodhart’s Law in action: when a measure becomes a target, it ceases to be a good measure. This episode goes back to 1975 and British economist Charles Goodhart watching the central bank chase money supply targets, then shows how banks under the Thatcher government invented products classified as broad money to sidestep narrow money restrictions, breaking the very relationship policymakers relied on.

The hosts then trace the same distortion through the accountability era: UK degree grades collapsing into a 2:1 baseline, No Child Left Behind narrowing curricula and forcing teaching to the test, scientists salami slicing papers and forming citation cartels to inflate their h-index, hospitals discharging patients early to cut length of stay and driving readmissions, and the UK’s 100,000 daily COVID test target being met by counting kits put in the mail. They also cover Campbell’s Law, Danielsson’s corollary on risk models, the colonial cobra bounty, and the IUCN’s deliberate reluctance to declare species extinct because doing so can strip habitat protections.

• Why Goodhart’s Law is morally neutral and does not require greed to take effect
• The map-territory problem and eating the menu instead of the meal
• How the cobra effect made Delhi’s snake problem worse
• Why a constellation of competing metrics beats any single number
• The fitness tracker you shake on the couch as a tiny version of the same glitch